Cross-linking of hemoglobin and inhibition of globin synthesis in reticulocytes induced by photoactivated protoporphyrin.
The photoactivated protoporphyrin effect on reticulocyte globin synthesizing capability, cross-linking of intracellular hemoglobin and the cell ultrastructural alterations was studied. Low doses up to 15 microM of protoporphyrin markedly inhibited the globin synthesis and decreased amino acid uptake while no lytic effect or ultrastructural deformations were detected by scanning electron microscopy and transmission electron microscopy. On the other hand, at high doses of protoporphyrin, up to 60 microM, the globin synthesis was totally stopped, and the intracellular hemoglobin leaked out. The photodynamic effect induced cross-linking of hemoglobin into condensed spheres which captured numerous polyribosomes. The end-product of protoporphyrin activity was a closed ghost with a rigid membrane containing only cross-linked hemoglobin spheres closely related to the membrane.
D000818:Animals; D005914:Globins / Q000096:biosynthesis*; D006454:Hemoglobins / Q000378:metabolism*; D066298:In Vitro Techniques; D008027:Light; D011166:Porphyrins / Q000494:pharmacology*; D011524:Protoporphyrins / Q000494:pharmacology* / Q000528:radiation effects; D011817:Rabbits; D012156:Reticulocytes / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D006454:Hemoglobins; D011166:Porphyrins; D011524:Protoporphyrins; D005680:gamma-Aminobutyric Acid; D005914:Globins